Recent growing concerns about environmental issues have led to an increasingly strong demand for higher fuel efficiency of automobiles. Thus, highly fuel efficient rubber compositions for use in automobile tires are also required. In order to improve fuel efficiency; rubber compositions for automobile tires are designed using a technique of reducing the filling ratio of carbon black or a technique of incorporating a filler such as silica to reduce the energy loss; tires are designed using a a technique of reducing the weight of tires to reduce the energy loss. However, if the weight of a tire is reduced by reducing the amount of carbon black or by reducing the volume of a sidewall rubber (i.e. by reducing the thickness of a side-wall), then an increase in the electrical resistance of the tire may be caused, which may lead to radio noise or cause an electrical discharge daring fueling to ignite gasoline.
For example, Patent Literature 1 suggests a tire that is provided with a highly electrically conductive rubber layer to suppress an increase of the electrical resistance of a tire, and has achieved a reduction in weight. However, although this method ensures conductivity of the lightweight fire, the rubber stiffness of the side of the tire is reduced with a reduction in the volume of a sidewall rubber, to cause deterioration in handling stability. Therefore, there still remains room for improvement in achieving fuel efficiency and handling stability at the same time.